/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date:        15. February 2012
* $Revision: 	V1.1.0
*
* Project: 	    CMSIS DSP Library
* Title:	    arm_pid_init_q31.c
*
* Description:	Q31 PID Control initialization function
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
*    Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.10 2011/7/15
*    Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
*    Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
*    Documentation updated.
*
* Version 1.0.1 2010/10/05
*    Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
*    Production release and review comments incorporated.
* ------------------------------------------------------------------- */

#include "arm_math.h"

/**
* @addtogroup PID
* @{
*/

/**
 * @brief  Initialization function for the Q31 PID Control.
 * @param[in,out] *S points to an instance of the Q31 PID structure.
 * @param[in]     resetStateFlag  flag to reset the state. 0 = no change in state 1 = reset the state.
 * @return none.
 * \par Description:
 * \par
 * The <code>resetStateFlag</code> specifies whether to set state to zero or not. \n
 * The function computes the structure fields: <code>A0</code>, <code>A1</code> <code>A2</code>
 * using the proportional gain( \c Kp), integral gain( \c Ki) and derivative gain( \c Kd)
 * also sets the state variables to all zeros.
 */

void arm_pid_init_q31(
    arm_pid_instance_q31* S,
    int32_t resetStateFlag)
{

#ifndef ARM_MATH_CM0

	/* Run the below code for Cortex-M4 and Cortex-M3 */

	/* Derived coefficient A0 */
	S->A0 = __QADD(__QADD(S->Kp, S->Ki), S->Kd);

	/* Derived coefficient A1 */
	S->A1 = -__QADD(__QADD(S->Kd, S->Kd), S->Kp);


#else

	/* Run the below code for Cortex-M0 */

	q31_t temp;

	/* Derived coefficient A0 */
	temp = clip_q63_to_q31((q63_t) S->Kp + S->Ki);
	S->A0 = clip_q63_to_q31((q63_t) temp + S->Kd);

	/* Derived coefficient A1 */
	temp = clip_q63_to_q31((q63_t) S->Kd + S->Kd);
	S->A1 = -clip_q63_to_q31((q63_t) temp + S->Kp);

#endif /* #ifndef ARM_MATH_CM0 */

	/* Derived coefficient A2 */
	S->A2 = S->Kd;

	/* Check whether state needs reset or not */
	if(resetStateFlag) {
		/* Clear the state buffer.  The size will be always 3 samples */
		memset(S->state, 0, 3u * sizeof(q31_t));
	}

}

/**
 * @} end of PID group
 */
